Therefore, by setting \(0\le \rho _{b1},\rho _{b2}\le 1 \) , we control the system's spectral radius \(\rho \)  and, consequently, the high-frequency numerical damping. Figure REF  shows how the user controls \(\rho \)  and the stability region \(\Omega _s\) ; setting \(\rho _b=\rho _s=0.99\)  leads to the largest stability region \(\Omega _s=4(\theta \tau )^2=4\Theta \) , equivalent to the stability region of the second-order central difference method [1]}.
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